Cutter assembly



June 9, 1959 w, WOQD 2,889,677

CUTTER ASSEMBLY Filed June 1l, 17956 2 Sheets-Sheet 1 Oil-fre moe: yf

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' CUTTER ASSEMBLY Filed June 11, 1956 v 2 sheets-sheet 2 mwfomoevfCUTTER ASSEMBLY Leonard W. Wood, Gregori, lll., assigner to WoodBrothers Manufacturing Co., Gregori, lll., a corpcration of illinoisApplication .lune 11, 1956, Serial No. 590,446

5 Claims. (Cl. 56295) This invention relates to a cutter assembly suchas is used on mowers and, more particularly, to an assembly in which oneor more blades are carried by a rotating support. vIn such an assembly,each blade projects laterally outwardly from the axis of rotation and ispivotally con nected to the support to swing back when it strikes anobstruction thus reducing the possibility of damage to the blade. Duringthe normal operation, the Iblade is maintained in an active position andswing `back only in the case of an obstruction.

The general object of the invention is to provide a new and improvedcutter assembly of the above character in which the blade, afterstriking an obstruction, is automatically returned to the activeposition in the continued operation of the cutter and in which the bladeis positively held in the active position during normal operation.

A more detailed object is to arrange the parts so as to utilizecentrifugal force for swinging the blade back to a positively determinedactive position whereby the cutter is reconditioned for operationautomatically and without being stopped.

The invention also resides in the novel construction used to pivot theblade on the rotating support and in the particular manner of holdingthe blade in the active position.

Other objects and advantages of the invention will become apparent fromthe following detailed description taken in connection with theaccompanying drawings, in which Figure l is a fragmentary plan view ofone form of cutter assembly embodying the novel features of the presentinvention, parts being broken away and shown in section.

Fig'. 2 is a fragmentary perspective view of the assembly.

Fig, 3 is a sectional view taken along the line 3-3 in Fig. 1.

Fig. 4 is a sectional view taken along the line 4-4 in Fig. l.

aFig. 5 is a View similar to Fig. 3 but shows the parts in a differentposition.

Fig. 6 is a fragmentary plan view of a modied form of the invention.

Fig. 7 is a view similar to Fig. 6 but with parts broken away showingone blade in the inactive position.

Fig. 8 is a fragmentary sectional View taken along the line 8-8 in Fig.6.

Fig. 9 is a fragmentary sectional View taken along the line 9-9 in Fig.6.

Fig. l is a fragmentary perspective view of another form of theinvention.

As shown in Figs. l through of the drawings, the invention in one of itsforms may be embodied in a cutter assembly comprising a support member10 rotatable about a generally vertical axis a and carrying a pluralityof elongated blades l1 projecting laterally from and generally radiatingwith respect to the axis a. Herein, the support 10 is a at platedisposed horizontally and Patented June 9, 9

pressed onto the lower end of an upright shaft 12 which is turned by asuitable power actuator (not shown). The blades 11, which in this caseare two in number, are in the form of elongated flat bars disposed onopposite sides cf the shaft 12 in a plane normal to the axis a andmounted on the support plate 10 to turn bodily therewith. The barsextend outwardly from the support and, along their outer end portions,the bars are sharpened on the leading edge as indicated at 13 in Fig. l.

To prevent damage to the blades 11, each blade is mounted on the plate10 for movement relative thereto when the blade strikes an obstructionso that, in such an event, the blade yields instead of breaking. In thepresent instance, each blade is pivotally connected at its inner end tothe plate 10 by means of a pin 14 which projects through the plate andthe blade so that the blade swings relative to the plate about an axis b(Fig. 4) parallel to the axis a. Thus, the blade normally is disposed inthe active position shown in full in Fig. l but, when it hits anobstruction such as a stone. or a stump, it swings back toward theinactive position (illustrated in Ibroken lines in Fig. l) until itpasses clear of the obstruction.

in accordance with the present invention, the parts are arranged in anovel manner to utilize centrifugal force to return the blade 11 to theactive position automatically as soon as the blade passes clear of theobstruction and, additionally, to hold the blade positively against arigid stop i6 when the blade is in the active position. This is achievedby permitting the blade to swing freely in the direction opposite itsdirection of rotation and by locating the stop so that it holds theblade back of the radial position. With this arrangement, the blade mayswing back when it strikes an obstruction and then, after it passesclear of the obstruction, the centrifugal force swings the .bladeforward and holds it in the active position against the stop.

ln the present instance, the inner end portion of each blade 1i isdisposed Within a horizontal slot 17 cut in the plate 1h and openingoutwardly and rearwardly to permit swinging of the blade. The pin 14,therefore, projects through holes 18, 19 and 20 (Fig. 4) in the upperleg portion 21 of the plate (see Fig. 4), the blade, and the lower legportion 22 respectively. When in the active position, the blade abutsagainst the forward wall of the slot and, thus, this `wall constitutesthe stop 16.., ,A.,projec tion 23 on the side edge of the plate forms a'second 'stop which limits the rearward swinging of the blade. l

Centrifugal force alone may be used to hold the blade in the activeposition or this may be supplemented by additional means which holdseach blade 11 in the normal or active position but permits the blade toswing back rto the inactive position when it strikes an obstruction.According to the present invention, this means, when employed, isconstructed in a novel manner to permit the blade to be returned to the'active position simply and easily and without removing or replacing anyparts. For this purpose, this means comprises' a yieldable detent 15which, when the blade is in the active position, engages a trailing edgeof the blade urging the latter forward against the stop` 16. When anobstruction is encountered, the detent yields permitting the blade toswing back away from the active position. Similarly, the detent yieldslas the blade is returned Vso that the cutter is reconditioned foroperation simply by swinging the blade back to the active position.

Each detent may, as illustrated, be in the endportion of a strip 24 ofresilient materialsuch as spring steel anchored at one end near theleading edge of the plate 10 as by rivets 25 and extending across thetop ofthe plate with a portion near the free end of the 'strip' bentdown to project it behind the trailing edge of the blade and the stripupwardly as shown in broken lines, the

detent being inclined slightly to facilitate lthis action. The bladethen is free to move past the detent and swing toward the inactiveposition.

To permit the blade 11 to be returned to the active position, the strip24 is formed with a cam 26 which,

when engaged by the blade, lifts the detent 15 and permits the blade toenter the slot 17. As the blade reaches the active position, the detentsnaps black behind the blade to hold the latter against the stop 16.Herein, the cam 26 is an extension of the strip 24 and projectsoutwardly and upwardly from the lower end of the detent portion of thestrip. Due to the inclining of the free end portion of the strip, theblade 11 as it is returned to the slot cams the strip upwardly as shownin Fig. so that the blade passes under the detent 15.

In order to take advantage of centrifugal force to return the blades 11to the active position, the blades generally radiate from the axis awhen in the cutting position. Since centrifugal force tends to move theblades radially, this force urges the blades toward the active position.As soon as a blade passes around the obstruction, therefore, it swingsforward under the action of centrifugal force and enters the slot 17,the detent 15 snapping in behind the blade. Preferably, the slots 17 andhence the blades 11 are inclined slightly rearwardly from a true radialposition so that they are urged continuously against the stops 16 bycentrifugal force and thus are positively located and rmly held in thelactive cutting position.

According to another aspect of the invention, the pivot pin 14 isarranged and held in place in a novel manner so that it may be taken outeasily when it is desired to replace a blade or remove one forsharpening. To this end, the head 27 (Fig. 4) of the pin is countersunkin the leg 21 of the plate 10 so as to be flush with the latter and isloosely received in the holes 18, 19 and 20. The pin is held down in thelatter by a member 28 which herein is a at strip of spring steeloverlying the pin. 29 extending through the plate 10 adjacent theleading edge thereof. This permits the strip to be moved so as to exposethe pin 14 for removal.

Normally, the strip 28 is held in position over the pin 14 and this isachieved by bending down the free end portion 30 of the strip to projectthe same into a notch 31 cut in the trailing edge of the plate 10. Thenotch is curved and the bent portion 30 -normally projects into thedeepest part of the notch. Thus, both sides of the portion 30 engage theedge of the plate 10 and this holds the strip 28 against turning innormal service use. In order that the strip may be turned manually,however, the end portion is cut diagonally to form a cam surface 32along the lower edge thereof. The cam surface acts when the strip isturned (clockwise as viewed in Fig. 1) to lift the strip end and permitthe strip to be turned away from the pin 14 to the position shown inbroken lines in Fig. l.

To permit easy turning of the strip 28 by a conventional tool, a part 33is secured to the strip 28 and is adapted to be engaged by the tool.Herein, the part 33 is a narrow plate welded to the top of the pivotedend portion of the strip 28. The end of the plate 33 forms, in eiect,three sides of a square nut concentric with the rivet 29 so that thisend may be gripped and turned by an ordinary wrench thus turning thestrip 28.

Figs. 6 through 9 illustrate a form of the invention in which thecentrifugal force alone holds the blades 11 in the `active. position. lnthis case, the cutter support is formed by two horizontal rectangularplates 21 and The retaining strip 28 turns on a rivet 22 (Figs. 8 and 9)held apart and joined together by narrow spacers 34. The latter aredisposed at the two leading corners of the plates and extend inwardlyalong the leading edge of the support to points alongside the pivots 14for the blades. The inside surfaces of the spacers are inclined to holdthe blades slightly behind the radial position, the same as in theembodiment shown in Figs. l through 5.

With the foregoing arrangement, the blades 11' are free to swing backsince the space or slot 16 (Fig. 8) between thc plates 2i and 22 isclear along the trailing edge portions of the support 10'. By employinga novel connection between the shaft 12 and the support 10', the amountthe blades can swing back is increased, the blades in the presentinstance being free to swing through approximately degrees. This permitsthe blades to pass obstructions more easily and is achieved by stoppingthe shaft 12' Short of the space between the plates 21 and 22 so thatthe blades can swing in under the shaft. Herein, the connection isformed by reducing the lower end portion 35 of the shaft and byprojecting this reduced portion into a hole 36 in the upper plate 21',the end of the shaft being ush with the underside of this plate. Theshaft is welded to the plate as indicated at 37 in Fig. 9. Thus, theblades may swing back until they strike the opposite spacer 34. In thisway, the inside or trailing surface of each spacer acts as a stop tohold the adjacent blade in the projected or active position and theinner end acts as a stop to limit backward swinging of the other blade.

Figs. 6 through 9 also illustrate another form of means for pivoting theblades 11 to the support 10 while permitting the blades to be removedquickly and easily. This means comprises a pivot pin 14 which extendsthrough both plates 21 and 22 and a blade 11 and a member 38 whichslides over the top of the pin and prevents the latter from coming out.The pin 14 has a head 39 which is received in a counterbore 40 in theplate 21 and keeps the pin from dropping out. The head is flush with thetop of the upper plate and the member 38 is a short bar which slides onthis plate into a position in which one end portion overlies the head ofthe pivot pin as shown in Fig. 8.

Herein, the bars 38 are arranged so that they are held in the activeposition shown in Fig. 8 by centrifugal force and, for this purpose, thebars are disposed inwardly of the pivot pins 14 and, in moving to theactive position, slide outwardly. The bars may, as illustrated in thedrawings, slide in inverted U-shaped brackets 41 welded to the upper barto define channels inclined to the radius of the cutter assembly. Thebars slide back and forth in these channels and the movement of each islimited by a pin 42 which projects through the bracket 41, an elongatedslot 43 in the bar and into the upper plate. The slot permits 4the barto move back to the inactive position shown at the left in Fig. 6 andforward to the active position shown at the right of that gure.

The parts may be arranged so that the bars 38 slide rather freely in theybrackets 41. In this way, the blades 11 may easily be removed simply bysliding the appropriate bar back and taking out the pivot pin 14. Whenthe blade and pin have been replaced, the bar is moved back to itsactive position. Because the bar moves generally radially outwardly tothe active position, centrifugal force holds it in this position and itwill even move the bar to the active position if the operator shouldneglect lto do this.

Another form of retaining means is illustrated in Fig. l0 and as in thecase of Fig. 6 this means is responsive to a centrifugal force whichholds the means in the position to prevent the pivot pin 14 from beingremoved. In this instance, the retaining means is in the form of a shortbar 44 which is pivotally connected intermediate its ends to the support10 on top of the upper plate 21'. The bar is pivoted by means of a pin45 which is spaced radially outwardly from the main pivot pin 14. Thebar 44 is located so that, when it is in a generally radial position asillustrated in Fig. 10, its inner end overlaps the head of the pin 14and thus holds the latter in place. By turning the bar to a transverseposition, the pin 14 may be removed.

With the foregoing arrangement, centrifugal force tends to swing the bar44 to a position in which it lies along a radius of the cutter assembly.This is the position in which it overlies the pin 14. Preferably the baris pivoted somewhat behind its center so that the outer portion islarger 'than the inner portion. Thus, a greater portion of the mass ofthe bar is at one side of the pin 45 and the effect of the centrifugalforce is greater on this side than it is on the other. In this way, thecentrifugal force will tend to swing the bar to the radial position eventhough the bar initially is in a true transverse position.

If desired, the bar may be held in the active or locking position by ascrew 46 which projects through the bar and is threaded into the upperplate 21. It should be understood, however, that in most instances thescrew is unnecessary and that the bar will remain in the lockingposition under the action of centrifugal force alone.

It will be observed that, with the cutter assembly described above, theblades 11 are returned easily to the active position after striking. anobstruction. In fact, the centrifugal force due to the continued turningof the support plate causes .the blade to snap back into the activeposition as soon as the blade passes clear of the obstruction. Moreover,the entire assembly is simple in construction and comparativelyinexpensive to manufacture. Additionally, either novel manner of holdingthe pivot pins 14 in place permits the blades to be removed quickly andeasily when it is desired to sharpen or replace them.

This application is a continuation-impart of my copending applicationSerial No. 479,425, led January 3, 1955, now abandoned,

I claim as my invention:

l. A cutter assembly for a rotating blade type mower comprising a poweroperated shaft, an elongated plate rigidly secured to an end portion ofsaid shaft and located in a plane normal to the axis thereof, a secondelongated plate member spaced from and parallel to said rst mentionedplate, spacer means interconnecting opposite terminal side edges of saidrespective plates, and two elongated cutter blades, one pivotallyconnected to each of the terminal end portions of said plate members,one side edge of each of said blades normally lying alongside of each ofsaid spacer means.

2. A cutter assembly for a rotating blade type mower comprising a poweroperated shaft, an elongated plate rigidly secured to an end portion ofsaid shaft and located in a plane normal to the axis thereof, a secondelongated plate spaced from and parallel to said rst mentioned plate,spacer means disposed between said plates at opposite ends thereof andalong the leading edges of the plates and interconnecting the plates toform a unitary support rigid with said shaft, and two elongated cutterblades, one pivotally connected to each of the terminal end portions ofsaid plates, one side edge of each of said blades normally lyingalongside of each of said spacer means.

3. A cutter assembly as delined in claim 2 in which said spacer meansholds said blades behind a true radial position.

4. A cutter assembly for a rotating blade type mower comprising a poweroperated shaft, an elongated plate rigidly secured to an end portion ofsaid shaft and located in a plane normal to the axis thereof, a secondelongated plate member spaced from and parallel to said rst mentionedplate, two spacer means disposed between said plates at opposite endsthereof and along the leading edges of the plates and interconnectingthe plates to form a unitary support rigid lwith said shaft, and twoelongated cutter blades, one pivotally connected to each of the terminalend portions of said plate members, one side edge of each of said bladesnormally lying alongside the adjacent spacer means and the rearwardswinging of the blade being limited by the opposite spacer means.

5. A cutter assembly for a rotating blade type mower comprising a poweroperated shaft, an elongated plate rigidly secured to an end portion ofsaid shaft and located in a plane normal to the axis thereof, a secondelongated plate spaced from and parallel to said rst mentioned plate,spacer means disposed between said plates at opposite ends thereof andalong the leading edges of the plates and interconnecting the plates toform a unitary support rigid with said shaft, two elongated cutterblades disposed at opposite ends of said plates and each having an endportion projecting in between the terminal end portions of said plates,pins projecting loosely through said plates and the inner end portionsof said blades to pivotally connect the blades to said plates, said pinshaving exposed heads, and elements mounted on said support to move backand forth between active positions in which they overlie the heads ofsaid pins and inactive positions alongside the heads, said elementsbeing responsive to said centrifugal force and held in the activepositions thereby.

References Cited in the file of this patent UNITED STATES PATENTS2,232,261 Orr Feb. 18, 1941 2,529,797 Cauble Nov. 14, 1950 2,529,870Golasky Nov. 14, 1950 2,592,755 Socnksen Apr. 15, 1952 2,634,571Lawrence et al Apr. 14, 1953 2,716,323 Ford Aug. 30, 1955 2,770,085Laughlin Nov. 13, 1956 2,777,268 Breed Jan. 15, 1957

